Suction cleaning head

ABSTRACT

A suction cleaning head (10) characterised in that it comprises a suction chamber (12) having an open mouth (36) and an outlet (40) adapted to be connected to an air extraction means, a cleaning liquid chamber (14) located at a point external to the suction chamber (12) and having an open mouth (63) and an outlet (62) adapted to be connected to a supply of cleaning liquid, a flow restricting means (16) adapted to engage the open mouth (63) of the cleaning liquid chamber (14), and a plurality of passageways (78, 122, 192) to enable transfer of cleaning liquid from the cleaning liquid chamber (14) through or past the flow restricting means (16).

DESCRIPTION

The present invention relates to a suction cleaning head. Moreparticularly, the present invention relates to a suction cleaning headintended for use with wet suction apparatus to clean carpets and othernatural and synthetic floor coverings including pile type rugs,upholstery and the like.

FIELD OF THE INVENTION

Typically, one form of wet suction cleaning apparatus presently in useto clean carpets, floor coverings, upholstery and the like is known as ahot water extraction cleaner or carpet steam cleaner. Such apparatustypically comprises a spray type cleaning head which is connected by aflexible suction hose to a source of suction capable of recovering andstoring liquids with the dirt or soils in suspension from the surfacesbeing cleaned. Such apparatus also comprises a separate cleaning liquidtank which is fitted with a high pressure pump such that cleaningliquids at various required temperatures may be sprayed onto the surfacebeing cleaned via jets generally located behind the cleaning head andconnected to this pump with a pressure hose.

The typical spray type cleaning head used in conjunction with this typeof apparatus is often triangular in shape when viewed from the front orrear and enclosed at the sides to form an open mouth suction chamberwith a tubular outlet at the top. This outlet is connected to a suctionsource through a hollow handle and a flexible vacuum hose. A separatepressure hose carries cleaning liquids at various required temperaturesto jets located behind the head that deliver a fan shaped spray to thesurface being cleaned. The supply of cleaning liquid is regulatedmanually by an operator controlled on/off valve. Generally the operatorsprays cleaning liquid onto the surface being cleaned whilst moving thecleaning head forward in an outward stroke. Then with the control valveoff, the operator draws the cleaning head backwards to suck up dissolveddirt or soils. In the case of a carpeted floor surface, the operatorgenerally exerts a downward pressure on the cleaning head during thebackward stroke which assists suction recovery by squeezing surpluscleaning liquid from the carpet fibres.

A difficulty with these spray type cleaning heads is the possibility ofoverwetting the surface being cleaned causing shrinkage, staining orprolonged drying as the flow of cleaning liquid must be regulatedmanually using the on/off valve and it is possible for an inexperiencedoperator to miscalculate the quantity of cleaning liquid required.

An additional difficulty occurs when higher temperature cleaning liquidsare required with spray type cleaning heads to accelerate the cleaningaction on exceptionally dirty or greasy surfaces. This difficulty is dueto the reduction in temperature that occurs as the cleaning liquid isdischarged to atmosphere prior to coming into contact with the surfacebeing cleaned. The jets are mounted well above the surface for effectivespray coverage which aggravates the cooling problem.

A further difficulty with spray type cleaning heads is that they have avery narrow opening between the front and back walls of the suctionmouth, typically 6 mm across the entire width of the suction chamber, sothat negligible downward force occurs due to atmospheric pressure whenair is evacuated from within the head during the cleaning of carpetedfloor surfaces. Any downward force needed to squeeze surplus cleaningliquid from carpet fibres must be provided by the operator. This istiring and uneven pressure may cause damage to older carpets.

A still further difficulty is the substantial cost of high pressurepumps required to deliver cleaning liquid to the jets behind spray typecleaning heads and the problem of maintenance if a pump runs dry or ablockage occurs.

Another form of wet suction cleaning apparatus is disclosed in UnitedKingdom Patent Application Nos. 1,121,225 and 1,291,138 which operatesin a similar manner to the more common form of hot water extractioncleaner or carpet steam cleaner but without a high pressure pump. Thisapparatus utilizes suction means to supply and remove cleaning liquidfrom the surface being cleaned. This form of apparatus incorporates asuction type cleaning head, an example of which also is disclosed.Further suction type cleaning heads are disclosed in InternationalPatent Application Nos. PCT/AU88/00446 and PCT/AU88/00447.

A difficulty with the suction type cleaning head or nozzle disclosed inUnited Kingdom Patent Application Nos. 1,121,225 and 1,291,138 is thatthe feed of cleaning liquid is drawn by suction to a cross tube withteeth like projections that is centrally located within the nozzleacross its width. This central location within the suction chamber withan internal space to the front and rear walls of the nozzle, causes anycleaning liquid discharged from the teeth like projections to beimmediately lost to suction on either side of the cross tube. As thenormal operation of cleaning heads is a forward and backwards movement asubstantial portion of cleaning liquid is lost before it has time tothoroughly penetrate and dissolve any dirt or soils on the fibres of thesurface being cleaned.

An additional difficulty with the suction type cleaning heads or nozzlesdisclosed in British Patent Applications Nos. 1,121,225 and 1,291,138 isthat incoming air is continuously drawn into the nozzle during normaloperations from beneath both the front and rear walls which has animmediate cooling effect reducing the efficiency of higher temperaturecleaning liquids that are delivered centrally. A still furtherdifficulty with the suction type cleaning head or nozzle disclosed inUnited Kingdom Patent Application Nos. 1,121,225 and 1,291,138 is causedby the close proximity of the suction outlet to the centrally locatedcross tube and teeth like projections which causes cleaning liquid to bedrawn mainly from the middle limiting the effective working width totypically 125 mm for heads of this type. Such heads are thereforelimited for use with lower powered domestic cleaning apparatus and forsmaller floor areas due to the narrow effective working width.

A difficulty with the suction cleaning head disclosed in InternationalPatent Application Nos. PCT/AU88/00446 and PCT/AU88/00447 is that thecleaning liquid reception chamber and the liquid delivery chamber arealso both centrally located and inwardly spaced from the front and rearwalls of the suction head in the same manner as the centrally locatedcross tube with teeth like projections previously disclosed in UnitedKingdom Patent Application Nos. 1,121,225 and 1,292,138. In theabovementioned International Patent Applications side walls have beenprovided on the liquid delivery chamber to reduce the rapid loss ofcleaning liquid to the suction chambers on either side. However, as thenormal operation of most cleaning heads, including suction heads, is aforward and backward movement, a substantial quantity of cleaning liquidwill be removed simultaneously due to the location of suction chamberson both sides of the cleaning liquid delivery area within the cleaninghead.

This reduces the cleaning effect of the liquid and in particular removesthe advantage of using higher temperature liquids that require a dwelltime to act upon and dissolve grease or ingrained soils from surfacesprior to removal. A further difficulty with the suction cleaning headsdisclosed in International Patent Application Nos. PCT/AU88/00446 andPCT/AU88/00447 is caused by the baffles in the form of Y-shaped orV-shaped ribs or vanes which deflect incoming air sideways within thesuction chamber. These baffles are positioned substantially across theflow of air into the suction mouth which reduces the efficiency of thehead due to the sudden changes of direction of the airflow andfrictional losses against these restrictive surfaces. The more thatpower and airflow are increased the more restrictive the baffles becomewhen compared to a cleaning head without restrictions. Typically suctionheads of the kind disclosed are 200 mm or less in effective workingwidth and are used in conjunction with smaller domestic cleaningapparatus.

A still further difficulty with these suction heads is caused by thepresence of an inner liquid reception chamber serving as a storagereservoir within the cleaning head. Whenever the accompanying source ofsuction is turned off, for example during emptying, refilling oradjustment, the contents of the inner liquid reception chamber dump bygravity flow onto the surface being cleaned in a series of over wetpatches. The alternative is to drain the internal reservoir bydisconnecting or shutting off the liquid supply and waiting for thecontents to be drawn away with the suction source still operating whichis time consuming. The present invention provides an improved andsimplified cleaning head that consists of two main components and issuited for use with any form of wet cleaning apparatus or wet suctionsource designed to recover liquids whether used for smaller domestic orlarger commercial purposes.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention there is provideda suction cleaning head comprising a suction chamber having an openmouth and an outlet adapted to be connected to an air extraction means,a cleaning liquid chamber located at a point external to the suctionchamber and having an open mouth and an outlet adapted to be connectedto a supply of cleaning liquid, a flow restricting means adapted toengage the open mouth of the cleaning liquid chamber, and a plurality ofpassage ways to enable transfer of cleaning liquid from the cleaningliquid chamber through or past the flow restricting means. The suctionchamber and cleaning liquid entry chamber preferably share a commonwall.

The liquid flow passageways may be formed in the flow restricting means.Alternatively, the liquid flow passageways may be formed as recesses orgrooves in one or more walls of the liquid entry chamber. Still furtherthe liquid flow passageways may be present in both the flow restrictingmeans and walls of the liquid entry chamber. The flow restricting meansis preferably adapted to fit over the open mouth when engaged therewithin a first embodiment of the present invention but may alternatively bereceived solely within the open mouth as in a second embodiment of thepresent invention.

The flow restricting means prevents movement of the cleaning liquid fromthe cleaning liquid chamber except through the liquid flow passagewaysprovided in either or both the flow restricting means and mouth of thecleaning liquid chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a front view of a suction cleaning head in accordance with afirst embodiment of the present invention;

FIG. 2 is a rear view of the suction cleaning head of FIG. 1;

FIG. 3 is a bottom plan view of the suction cleaning head of FIG. 1;

FIG. 4 is a cross-sectional side elevation of the suction cleaning headof FIG. 1;

FIG. 5 is a cross-sectional side elevation of the suction cleaning headof FIG. 1 with the flow restricting means detached;

FIG. 6 is a rear view of the suction cleaning head of FIG. 1 with theflow restricting means removed;

FIG. 7 is an upper perspective view of the flow restricting means ofFIGS. 4 and 5;

FIG. 8 is a cross-sectional side elevation of the suction cleaning headof FIGS. 1 to 4 shown in use on a carpet;

FIG. 9 is a front view of a suction cleaning head in accordance with asecond embodiment of the present invention with some internal featuresshown in phantom;

FIG. 10 is a rear view of the suction cleaning head of FIG. 9;

FIG. 11 is a bottom plan view of the suction cleaning head of FIG. 9;

FIG. 12 is a cross-sectional side elevation of the suction cleaning headof FIG. 9;

FIG. 13 is a cross-sectional side elevation of the suction cleaning headof FIGS. 9 to 12 shown in use on a carpet;

FIG. 14 is a cross-sectional side elevation of the suction cleaning headof FIG. 9 having a different flow restricting means fitted therein;

FIG. 15 is a perspective view of the flow restricting means of FIG. 14;

FIG. 16 is a cross-sectional side elevation of the suction cleaning headand flow restricting means of FIG. 14 shown in use on a carpet;

FIG. 17 is a cross-sectional side elevation of the suction cleaning headof FIG. 9 having a further different flow restricting means fittedthereto;

FIG. 18 is a bottom plan view of the suction cleaning head of FIG. 9having a still further different flow restricting means fitted thereto;

FIG. 19 is a perspective view of the flow restricting means of FIG. 18;

FIG. 20 is a cross-sectional side elevation of the suction cleaning headand flow restricting means of FIGS. 18 and 19;

FIG. 21 is a bottom plan view of the suction cleaning head of FIG. 9having a still further different flow restricting means fitted thereto;and

FIG. 22 is a cross-sectional side elevation of the suction cleaning headand flow restricting means of FIG. 21 shown in use on a carpet.

DESCRIPTION OF THE INVENTION

In FIGS. 1 to 8 there is shown a suction cleaning head 10 in accordancewith a first embodiment of the present invention. The suction cleaninghead 10 comprises a suction cheer 12, a cleaning liquid chamber 14(hereinafter referred to simply as the liquid chamber 14) and a flowrestricting means 16 which typically includes a closure and passageways,as will be subsequently explained.

The suction chamber 12 is defined by a forward wall 18, a rear wall 20and side walls 22. The forward wall 18 has an inner face 24 and an outerface 26. The rear wall 20 has an inner face 28 and an outer face 30.Similarly, the side walls 22 have inner faces 32 and outer faces 34. Thewalls 18, 20 and 22 of the suction chamber 12 define an open mouth 36.

The walls 18, 20 and 22 meet at a point remote from the open mouth 36 toform an outlet port 38 from which extends a suction hose connectingmeans 40. The connecting means 40 is adapted to receive a detachabletubular handle (not shown) which may be connected via a flexible suctionhose to a wet suction source designed to recover liquids (not shown).

A lower edge 42 of the forward wall 18 has provided thereat a forwardlyprojecting and elongated foot 44. The side walls 22 each have a loweredge 46 located in the same plane as a lower surface 48 of the foot 44.The rear wall 20 has a lower edge 50 spaced upwardly from the plane ofthe lower surface 48 of the foot 44 and the lower edge 46 of the sidewalls 22, as can be best seen in FIG. 5.

The liquid chamber 14 is defined by the rear wall 20 of the suctionchamber, a rearmost wall 52, an upper wall 54 and the side walls 22,again best seen in FIG. 5. The rearmost wall 52 has an inner face 56, anouter face 58 and a lower edge 60.

The upper wall 54 has located therein a liquid entry aperture 62 capableof having connected therein or thereto a tube means (not shown) in turnconnected to a source of cleaning liquid (not shown).

The walls 20, 22 and 52 define an open mouth 63. The lower edge 60 ofthe rearmost wall 52 is again spaced upwardly from the plane of thelower surface 48 of the foot 44 and the lower edges 46 of the side walls22. However, the lower edge 60 is closer thereto than the lower edge 50of the rear wall 20.

The rear wall 20 and rearmost wall 52 have provided therein slots 64adjacent the side walls 22, as can be seen in FIG. 6. The slots 64 allowthe flow restricting means 16 to be received therein.

The flow restricting means 16 comprises a base member 66, upstandingforward and rear walls 68 and 70 respectively, and side walls 72, as isbest seen in FIG. 7.

The base member 66 has an upper surface 74 and a lower surface 76. Aplurality of passageways 78 are provided in the base member 66 extendingfrom the upper surface 74 to the lower surface 76. The base member 66also has upstanding from its upper surface 74 a stud member 80. The stud80 does not touch or interconnect with the forward and rear walls, 68and 70 respectively.

The forward wall 68 has projecting therefrom a reinforcing member 82, ascan be seen in FIGS. 4, 5 and 7. The lower surface 76 of the base member66 has provided thereon a depending forward edge 84 and a rearwardlyprojecting edge 86.

The side walls 72 have provided therein recesses 88 adjacent the forwardand rear walls, 68 and 70 respectively. The flow restricting means 16attaches to the liquid chamber 14 as shown in FIG. 4 and substantiallyencloses the same. The recesses 88 and the stud member 80 engage therear wall 20 and rearmost wall 52. The reinforcing member 82 engages theinner face 24 of the forward wall 18. The rearwardly projecting edge 86of the lower surface 76 lies in substantially the same plane as thelower surface 48 of the foot 44 and the lower edges 46 of the side walls22, as can be seen in FIG. 4. The forward edge 84 of the lower surface76 is positioned upwardly from this plane. In FIG. 8 there is shown thesuction cleaning head 10 in use on a carpet 90. The carpet comprises abase 92 and fibres 94 projecting therefrom.

In FIGS. 9 to 22 there is shown a suction cleaning head 100 inaccordance with a second embodiment of the present invention. Thesuction cleaning head 100 is in part the same as the suction cleaninghead 10 and like numerals denote like parts.

The flow restricting bar 16 is not present in the suction cleaning head100. The rearmost wall 52 has provided at its lower edge 60 a rearwardlyprojecting foot 102 having a lower surface 104. The lower surface 104lies in substantially the same plane as that defined by the lowersurface 48 of the foot 44 and the lower edges 46 of the side walls 22,as can best be seen in FIG. 12.

The position of the lower edge 50 of the rear wall 20 in the suctioncleaning head 100 is substantially equivalent to that of the forwardedge 84 in the suction cleaning head 10 with the flow restricting means16 attached thereto. The inner face 24 of the forward wall 18 haslocated therein a number of recesses 106 that extend from the lower edge42 thereof. The inner face 28 of the rear wall 20 also has locatedtherein a corresponding number of recesses 108 extending from the loweredge 50 thereof.

A spacer means 110 is received in corresponding pairs of recesses 106and 108, as can be best seen in FIGS. 11 and 12. The spacer means 110thereby spaces the walls 18 and 20 apart.

A flow restricting means 112 is provided to fit into the open mouth 63of the liquid chamber 14, as can be seen in FIGS. 11 and 12. The flowrestricting means 112 has a forward face 114, a rear face 116, a lowerface 118 and an upper face 120. The forward face 114 has located thereina plurality of passageways 122 extending between the lower face 114 andthe upper face 120.

The flow restricting means 112 is received in the open mouth 63 in amanner such that the lower face 118 extends from the lower edge 50 ofthe rear wall 20 to the lower edge 60 of the rearmost wall 52, as shownin FIG. 12.

In FIG. 13 there is shown the suction cleaning head 100 with the flowrestricting means 112 therein in use on the carpet 90.

In FIG. 14 there is shown the suction cleaning head 100 having therein aflow restricting means 130. The flow restricting means 130 has a forwardface 132, a rear face 134, a lower face 136 and an upper face 138, ascan be seen in FIGS. 14 and 15. The forward face 134 having thepassageways 122 located therein as described above.

The lower face 136 extends from a point above the lower edge 50 of therear wall 20 to substantially the lower edge of the rearmost wall 52, asis best seen in FIG. 14. The upper face 138 and lower face 136 aresubstantially parallel.

In FIG. 16 there is shown the suction cleaning head 100 with the flowrestricting means 130 therein in use on the carpet 90.

In FIG. 17 there is shown the suction cleaning head 100 having therein aflow restricting means 150. The flow restricting means 150 has a forwardface 152, a rear face 154, a lower face 156 and an upper face 158, asshown in FIG. 17.

The forward face 152 has the passageways 122 located therein asdescribed above. The forward face 152 is substantially shorter in lengththan the rear face 154. The upper face 158 is substantially straight andflat thereby the lower face 156 has a flat portion 160 and a curvedportion 162. The flat portion 160 is adjacent the rearmost wall 52 andthe curved portion 162 adjacent the rear wall 20, as shown in FIG. 17.The passageways 122 open into the curved portion 162 of the lower face156. The curved portion 162 meets the rear wall 20 at a point above thelower edge 50 thereof.

In FIGS. 18 and 20 there is shown the suction cleaning head 100 havingtherein a flow restricting means 170. The flow restricting means 170 hasa forward face 172, a rear face 174, a lower concave face 176 and anupper face 178, as shown in FIGS. 19 and 20 especially.

A plurality of apertures 180 are provided extending from the upper face178 to the lower concave face 176 substantially midway between theforward and rear faces 172 and 174 respectively.

In FIGS. 21 and 22 there is shown the suction cleaning head 100 havingtherein a flow restricting means 190. The flow restricting means 190 issubstantially the same as the flow restricting means 150 and likenumerals denote like parts. The major difference being that the forwardface 152 of the flow restricting means 190 is flat and featureless.Passageways 192 are provided in the rear face 30 of the rear wall 20extending from a point higher than the upper face 158 to the lower edge50 of the rear wall 20, as can be seen in FIG. 22.

In use, the suction cleaning head 10 first has the flow restrictingmeans 16 fitted thereto by a user (not shown) so as to enclose theliquid chamber 14. The connecting means 40 is used to connect thesuction cleaning head 10 to the tubular handle in turn connected to aflexible suction hose and wet suction source for the recovery ofliquids.

The aperture 62 is connected to a source of preferably warm or hotcleaning liquid (not shown) via a flexible tube (not shown). The type ofcleaning liquid is governed by the surface to be cleaned and the type ofsoiling thereon. The suction source is activated and the open mouth 36of the suction chamber 12 placed against the carpet 90, as shown in FIG.8. Air is drawn into the suction chamber 12 predominantly under the sidewalls 22. Less air enters under the foot 44 and edge 86 because of theirlarger surface in contact with the carpet fibres 94 and the compressionthereunder.

Accordingly, a sub-atmospheric pressure zone is created within thesuction chamber 12. Normal atmospheric pressure acting on the suctioncleaning head 10 creates a downward force thereon. This actioncompresses the carpet fibres 94 and creates partial sealing under thefoot 44 and edge 86. The reinforcing member 82 prevents collapse of theforward wall 18 and narrowing of the open mouth 36 whereas the flowrestricting means 16 holds the rear wall 20 in position. As the suctioncleaning head 10 is moved forward over the carpet 90, as shown in FIG.8, fibres 94 are first compressed under the foot 44. The fibres 94 areuncompressed then within the open mouth 36 of the suction chamber 12. Arecompression of the fibres 94 will occur under the forward edge 84 ofthe flow restricting means 16. The fibres 94 upon passing the forwardedge 84 experience a reduced compression and preferably contact thelower surface 76 of the flow restricting means 16. The fibres 94 aresubsequently recompressed under the rearwardly projecting edge 86.

The sub-atmospheric pressure created within the suction chamber 12 istransferred under the forward edge 84 to an area under the lower surface76. This is in turn transferred to the liquid chamber 14 by thepassageways 78. This causes cleaning liquid to be drawn into the liquidchamber 14.

The cleaning liquid thereby drawn into the liquid chamber 14 firstcollects at the junction of the upper surface 74 and the rearmost wall52 forming a distribution channel. Once sufficient liquid has been drawnthereinto the liquid is drawn through the passageways 78 directly ontothe fibres 94.

This arrangement having the passageways 78 positioned, in a linearfashion, at a point remote to the point whereat the cleaning liquidfirst collects upon entering the liquid chamber 14 ensures the uniformtransfer of cleaning liquid to the carpet 90 across the width of thesuction cleaning head 10. The passage of cleaning liquid into the liquidchamber 14 is dependent upon the internal diameter of the tubingconnecting the aperture 62 and the source of cleaning liquid. The tubingis chosen so as to just fill the distribution channel. This prevents wetpatches on the carpet 90 due to dumping of cleaning liquid by gravityflow upon deactivation of the wet suction source.

The fibres 94 are thereby wetted directly with cleaning liquid oftenabsorbing the same through a capilliary action. Such wetting of thefibres 94 is characterised by absolutely minimal temperature loss in thecleaning liquid and more effective cleaning. Also, no high-pressure pumpis needed as sub-atmospheric pressure delivers the cleaning liquid.

The re-compression of the fibres 94 under the edge 86 may force thecleaning liquid deeper into the carpet 90 thereby increasing cleaningefficiency. The cleaning liquid is subsequently left to "dwell" in thecarpet 90 and is not immediately recovered as with prior art suctionheads having liquid distribution within the suction chamber. Thelocation of the liquid chamber 14 at a point external to the suctionchamber 12 makes this possible.

Upon the suction cleaning head 10 again passing over the area on eithera forward stroke or a back stroke the cleaning liquid will be drawn fromthe carpet fibres 94 in an uncompressed state in the open mouth 36 ofthe suction chamber 12.

Recovery of the cleaning liquid on the backstroke is further enhanced bythe lower edge 42 which is forced downward by atmospheric pressureacting on the suction cleaning head 10 which squeezes the cleaningliquid from the carpet fibres 94 before they pass beneath the lowersurface 48 of the foot 44. Cleaning liquid thereby collecting on theinner face 24 of the forward wall 18 is evacuated from the suctionchamber 12 by the suction force therein.

On the backstroke further cleaning liquid will be transferred to thecarpet 90. This will be worked into the carpet 90 upon passing under theedge 84 and then drawn from the fibres 94 into the suction chamber 12.The combination of the short and long "dwell" time of cleaning liquid inthe carpet 90 gives highly efficient cleaning thereof.

It is envisaged that the flow restricting means 16 could be setpermanently in place rather than being removable as indicated, howeverthe latter does provide advantages for cleaning of the suction cleaninghead 10.

The use of the suction cleaning head 100 in combination with the flowrestricting means 112, 130, 150, 170 and 190 is substantially the sameas that described for the suction cleaning head 10.

The spacer means 110 located in recesses 106 and 108 prevent thenarrowing of the open mouth 36 and prevent the rear wall 20 pulling awayfrom the flow restricting means 112, 130, 170 and 190.

With reference to FIG. 13 and flow restricting means 112 the operationis altered in the following ways. The re-compression of the carpetfibres 94 under the lower edge 50 of the rear wall 20 is notsubstantially relieved before the fibres 94 contact the lower face 118of the flow restricting means 112. The foot 102 thereafter compressesthe fibres 94 (when referring to the forward stroke). With reference toFIG. 16 and flow restricting means 130 the operation varies in thefollowing ways. Due to the angle of the lower face 136 and its junctionwith the rear wall 20 at a point above the lower edge 50 cleaning liquidtends not to be delivered directly onto the carpet 90 from thepassageways 122. On denser short pile or felt non-pile type carpets adistribution cavity may be formed below the rear face 30 of the rearwall 20 and the lower face 136. This assists the distribution ofcleaning liquid across a carpet 90 if heavily matted with dirt, greaseor the like. It should be noted that the fibres 94 still do contact atleast part of the lower face 136 of the flow restricting means 130 in arelatively uncompressed state thereby being able to accept the cleaningliquid.

With reference to FIG. 17 and flow restricting means 150 the operationis substantially the same as that for flow restricting means 130. Theuncompressed carpet fibres 94 contact at least the flat portion 160 ofthe lower face 156 whereas the distribution cavity is formed beneath thecurved portion 162 and adjacent the rear wall 20.

With reference to FIG. 20 and flow restricting means 170 the operationis substantially the same as that for flow restricting means 130. Thecleaning liquid is delivered to the carpet fibres 94 through apertures180. The distribution cavity may be formed under the concave lower face176 of the flow restricting means 170 when used on denser short pile orfelt non-pile type carpets.

With reference to FIG. 22 and flow restricting means 190 the operationis substantially the same as that for flow restricting means 150 withregard to the distribution cavity. However, cleaning liquid is deliveredto the distribution cavity through passageways 192 provided in the rearface 30 of the rear wall 20.

It is to be understood that the liquid cheer 14 may be provided also onthe forward wall 18. Accordingly, the procedure employed will need to bereversed to maintain cleaning efficiency.

It is further to be understood that it is preferable to not form adistribution cavity under the flow restricting means 112, 130, 150, 170and 190 but that it may occur with denser shorter pile or non-pilefelt-type carpets.

It is envisaged that for carpets such as these with limited compressionthe lower edge 50 of the rear wall 20 or the edge 84 of the flowrestricting means 16 will need to be closer to that plane of the foot 44and side walls 22. It is still further envisaged that the rear wall ofthe suction chamber is spaced well away from the front wall, preferablyat least 20 mm or greater to create a much larger area at the suctionmouth than conventional cleaning heads previously disclosed in priorart, which typically have a narrow gap of 10 mm or less. The advantagegained by enlarging the surface area of the suction mouth is that,during normal cleaning operations, a downward force is exerted on thecleaning head by atmospheric pressure when air is evacuated from withinthe suction chamber thus eliminating the need for the operator to exertdownward force manually to assist recovery by squeezing excess liquids,for example, from carpet fibres. This overcomes operator fatigue whencleaning larger areas.

The present invention provides a suction cleaning head operatingessentially because of the different rates of compression of the carpetfibres and variations in the resulting sealing effect in the carpet itis being used on. These variations in sealing effect are due to thevarying widths and heights of the different contact surfaces of thesuction cleaning head and to the extent and quantity of carpet fibresbeing compressed beneath them, as described previously.

Modifications and variations such as would be apparent to a skilledaddressee are deemed within the scope of the present invention.

I claim:
 1. A suction cleaning head, comprising:a suction chamber havingan open mouth and an outlet connectable to an air extractor; a cleaningliquid chamber positioned externally to said suction chamber and havingan open mouth and an inlet connectable to a supply of cleaning liquid,the cleaning liquid being flowable through said cleaning liquid chamber;and means for restricting the flow of the cleaning liquid through saidcleaning liquid chamber, comprising:a closure releasably engaging and atleast partially closing the open mouth of said cleaning liquid chamber;and a plurality of passageways formed at least in part by said closure,said passageways being in communication with said cleaning liquidchamber and enabling the cleaning liquid to flow from said cleaningliquid chamber at a rate restricted by a dimension and number of thepassageways.
 2. A suction cleaning head according to claim 1, whereinthe cleaning liquid chamber and the suction chamber at least in partshare a common wall.
 3. A suction cleaning head according to claim 1,wherein the suction chamber is defined by forward, rear and side wallsmeeting at the outlet at one end and forming the suction chamber openmouth at another end.
 4. A suction cleaning head according to claim 3,wherein the cleaning liquid chamber is located across the rear wall ofthe suction chamber, the cleaning liquid chamber being defined by arearmost wall, a plurality of side walls and the rear wall of thesuction chamber.
 5. A suction cleaning head according to claim 3,wherein a lower edge of the forward and side walls of the suctionchamber define substantially a single flat plane.
 6. A suction cleaninghead according to claim 5, wherein a lower edge of the rear wall of thesuction chamber and a lower edge of a rearmost wall of the cleaningliquid chamber define a plane located above and at an angle to thesingle flat plane.
 7. A suction cleaning head according to claim 6,wherein said closure is releasably attachable over the rear wall of thesuction chamber and rearmost wall of the cleaning liquid chamber tosubstantially enclose the cleaning liquid chamber.
 8. A suction cleaninghead according to claim 7, wherein said closure has a rearwardlyprojecting foot, a forward depending edge and a base member therebetweenhaving a flat to mildly concave lower surface, the base member havingprovided therein the passageways communicating between the cleaningliquid chamber and lower surface.
 9. A suction cleaning head accordingto claim 8, wherein the base member of said closure includes an uppersurface having a stud member locatable between the rear wall of thesuction chamber and rearmost wall of the cleaning liquid chamber whenthe closure is attached thereto.
 10. A suction cleaning head accordingto claim 8, wherein said closure includes a distribution channel formedat a junction of the base member and the rearmost wall for the gatheringof the cleaning liquid when said closure is attached to said cleaningliquid chamber.
 11. A suction cleaning head according to claim 7,wherein said closure includes a reinforcing member projectable into thesuction chamber to abut the forward wall thereof.
 12. A suction cleaninghead according to claim 3, wherein the forward wall has provided at alower edge thereof a forwardly projecting foot being substantially flaton an underside thereof.
 13. A suction cleaning head according to claim1, wherein said closure is received within the open mouth of thecleaning liquid chamber, and the cleaning liquid chamber includes arearmost wall provided with a rearwardly projecting foot.
 14. A suctioncleaning head according to claim 13, wherein the rearwardly projectingfoot lies in the same plane as a plane substantially defined by a loweredge of a forward and side walls of the suction chamber.
 15. A suctioncleaning head according to claim 13, wherein a lower face of theclosure, when fitted in the open mouth of the cleaning liquid chamber,defines a plane from a lower edge of a rear wall of the suction chamberto the rearward projecting foot of the rearmost wall, the closure havingthe passageways provided therein to allow the lower face to communicatewith the cleaning liquid chamber.
 16. A suction cleaning head accordingto claim 15, wherein the passageways are located adjacent the rear wallof the suction chamber, and a distribution channel for the cleaningliquid is formed by the closure means and the rearmost wall.
 17. Asuction cleaning head according to claim 13, wherein the suction chamberincludes at least one spacer means located therein, and a forward walland a rear wall of said suction chamber includes therein a plurality ofrecesses to receive the spacer means.
 18. A suction cleaning headaccording to claim 13, wherein a lower face of the closure, when saidclosure is fitted in the open mouth of the cleaning liquid chamber,defines a plane from a point above a lower edge of a rear wall of thesuction chamber to the rearwardly projecting foot of the rearmost wall,and the closure has the passageways provided therein allowing the lowerface to communicate with the cleaning liquid chamber.
 19. A suctioncleaning head according to claim 18 wherein the passageways are locatedadjacent the rear wall of the suction chamber, and a distributionchannel for the cleaning liquid is formed by the closure and therearmost wall.
 20. A suction cleaning head according to claim 13,wherein a lower face of the closure has both a flat surface and a curvedsurface, the closure having the passageways provided therein allowingthe lower face to communicate with the cleaning liquid chamber.
 21. Asuction cleaning head according to claim 20, wherein the passageways arelocated adjacent a rear wall of the suction chamber, and a distributionchannel for the cleaning liquid is formed by the closure and therearmost wall.
 22. A suction cleaning head according to claim 13,wherein a lower face of the closure has a concave surface, the closurehaving the passageways provided therein allowing the lower face tocommunicate with the cleaning liquid chamber.
 23. A suction cleaninghead according to claim 22, wherein the passageways are locatedsubstantially midway between a rear wall of the suction chamber and therearmost wall of the cleaning liquid chamber, and a distribution channelfor the cleaning liquid is formed by the closure and the rearmost wall.24. A suction cleaning head according to claim 13, wherein thepassageways are provided only in one of a rear wall of the suctionchamber and the rearmost wall.